This invention relates to planar battery separators, flat-pack batteries and the methods of making same. More particularly, this invention concerns a planar battery separator comprising a nonwoven fabric disposed on and across an open hot melt plastic grid and wherein the portion of the fabric on the plastic grid is of a very low fiber density, facilitating a strong intra-battery seal thus prohibiting electrolyte leakage therefrom.
Planar or flat-pack batteries, for example, the LeClanche type battery, having recently become more widely used because of the "mini" product and package market in existence today. Planar batteries have found their way into computers, calculators, film-packs for instant cameras, and the like, and have received wide-spread acceptance. However, they seem to suffer some major drawbacks. For example, their shelf life is rather short due to electrolyte leakage therein during storage and use. This disadvantage is due primarily to faulty and incomplete seals within the battery pack. Unless the battery seal is complete, it results in many failures and much frustration.
Prior art attempts to correct this deficiency have included U.S. Pat. Nos. 3,701,690; 3,784,414; and 3,899,355. The first patent mentioned, U.S. Pat. No. 3,701,690 describes a battery having a sealant impregnated into the separator; U.S. Pat. No. 3,784,414 discloses a battery sealant carrier having adhesive patches impregnated therein; and U.S. Pat. No. 3,899,355 discloses a battery assembly utilizing a particular adhesive mass. However, none of these adequately solves the problem, and none describe or claim the invention disclosed herein.